Coating process of articles such as automobile parts, electric apparatuses, electronic parts, building materials and the like, generally gives the articles physical/chemical resistance, ornamental property (that is, how aesthetic the articles look after coating), and the like by forming, on surfaces of the articles, a plurality of coating films having different functions. In many cases, spray coating is employed to form the coating films on the articles. The spray coating is advantageous in coating gaps and bag-shaped (cave-shaped) sections of the articles, and has an excellent transfer efficiency. Therefore, the spray coating is one of coating methods used in wide-ranging fields.
On the other hand, the spray coating has such problems: a wide space is required to carry out the spray coating; the spray coating is a costly process; the spray coating requires a complicate process control; etc. That is, in case where the spray coating is used to form a plurality of coating films on an article, the process of the spray coating is a multi-staged process in which the spraying steps for spraying coating materials and baking steps for baking the coating materials are repeated in turn. Thus, a manufacturing line of the multi-staged process requires a wide space. Moreover, because the coating steps and the baking steps are repeated in turn in multi-stages, it is complicate to manage the process of the spray coating. Further, the process of the spray coating consumes a large amount of energy.
In view of this, for decorative-appearance-making process (decoration), a film decoration method has been suggested as a method that has no such problems unlike the spray coating method, that is, as a method (i) that has no need of a wide space for coating, (ii) whose coating process is easy to manage, and (iii) that has a low energy consumption for providing the plurality of the coating films, that is, making the decorative appearance of the article. In the film decorating method, the placing of the film on an article, that is, decorative-appearance-making process of the article is carried out by using a laminate film in which a plurality of coating films are layered. In the film decoration method, the laminate film is placed on a surface of the article in such a manner that the laminate film is firmly adhered (adhered on) with the surface with no space therebetween, thereby giving the decorative appearance to the article, (for example, see (a) the Japanese Unexamined Patent Application, Tokukai, No. 2000-79796 (published on Mar. 21, 2000, (b) the Japanese Unexamined Patent Application, Tokukaihei, No. 10-58895 (published on Mar. 3, 1998.)
By placing the laminate film on the surface of the article, it is possible to form a plurality of coating films on the article without repeating the spraying steps and the baking steps in turn in multi-stages, unlike the spray coating method. Therefore, it is unnecessary to have a wide coating space for carrying out the coating unlike the spray coating method, and it is possible to attain easy process control. Further, decorative-appearance-making process of the article is carried out without multi-staged steps. Thus, it is possible to attain a lower cost production in terms of energy consumption and the like.
However, the conventional laminate film attaches importance to the processing property in order to be able to appropriately perform the formation of the coating films on the article in the decorative-appearance-making process. Therefore, there is necessity for making improvement in the ornamental property of the article having the decorative appearance by using the laminate film. In other words, for the film decoration method, no laminate film has developed, which has both (i) processing property in placing the laminate film on the article in the decorative-appearance-making process, and (ii) ornamental property of the article after the decorative-appearance-making process.
Here, the processing property refers to properties attained by the decorative-appearance-making process of the article by using the laminated film. The properties are: (1) appearance properties such as (i) surface smoothness of the laminate film on the surface of the article, (ii) reproducibility of a shape that the article has before the decorative-appearance-making process, (iii) and the like properties; (2) chemical properties such as durability of the laminate film, and the like properties; and (3) physical properties such as (a) firm adhesion property between the laminate film and the article, (b) mar resistance and impact resistance of the laminate film, and (c) the like properties. Moreover, the ornamental property indicates (4) a shining appearance that indicates how shiny (twinkling) the laminate film is, (5) light scattering property of the laminate film, (6) flip-flop property that indicates a contrast between a highlighted look and a shaded look of the laminate film.
In the decorative-appearance-making process in which a conventional laminate film is used, it is difficult to attain both the processing property and the ornamental property: the decorative-appearance-making process of the article with improved processing property conventionally results in low ornamental property, whereas the decorative-appearance-making process of the article with high ornamental property conventionally has a problem in processing property. Specifically, for example, in case of the decorative-appearance-making process for an automobile parts as the article to which the decorative appearance is to be given, the use of the conventional laminate film has a difficulty in attaining a metal-look appearance or a metallic appearance similar to a metal-look appearance or a metallic appearance attained in an automobile body by the spray coating. Therefore, in the decorative-appearance-making process of the article using the conventional laminate film, it is difficult to achieve an ornamental property equivalent to or better than that of the conventional coating methods such as the spray coating and the like.